Implementation Science to Accelerate Clean Cooking for Public Health

Introduction Three billion people cook with traditional biomass stoves and open fires. Results from the Global Burden of Disease (GBD) Study have estimated that the consequent household air pollution (HAP) causes almost four million premature deaths annually—a health burden borne largely by the poor, women, and children in low-income countries (Lim et al. 2012). HAP has been linked both to some of the major preventable causes of death in children (including low birth weight and respiratory infections), and to some of the most significant contributors of noncommunicable diseases (NCDs), morbidity, and mortality around the world: stroke, CVD, chronic pulmonary disease, lung cancer and eye disease, as well as several safety concerns such as burns, injuries, and gender-based violence associated with biomass collection and use (Lim et al. 2012). The challenge is to accelerate the widespread, sustained adoption of demonstrably clean cooking to promote public health. Implementation science has evolved to meet precisely this kind of complex, multidimensional challenge. Both the scale and the complexity of implementing cleaner household energy practices in lowand middle-income countries (LMICs) call for systematic attention, not only to supply costs and cooking behavior by (largely) the women in the household, but also to the household, community, and larger socioeconomic and environmental context of energy access, adoption, and use (Jeuland and Pattanayak 2012). Actions by multiple sectors (e.g., energy, banking, communication, and commercial services), beyond health, are needed. Poverty, access to services, home construction, climate, cultural traditions, gender differences in opportunity costs, and time preferences are just some of the persistent barriers to be addressed. In 2014, the World Health Organization (WHO) released its indoor air quality guidelines (IAQG) for household fuel combustion (WHO 2014). The guidelines were developed to address the public health burden from household air pollution. Development of these guidelines began with the previously published WHO air quality guideline values for specific pollutants, including for fine particulate matter (PM2.5) and carbon monoxide (WHO 2006, 2010) that drew on reviews of a wide range of evidence spanning fuel use, emission levels and testing, exposure levels around the world, health risks, impacts of interventions in everyday use on HAP, and factors influencing sustained adoption. One of the key conclusions from the IAQG was that, despite impressive exposure reductions of 50–80% in the best stove programs, in absolute terms average post-intervention concentrations remained well above the WHO interim target (35 μg/m3 annual mean)—that is, levels estimated to be necessary to yield significant health improvements (WHO 2014). Based on the limited data available at the time, clean fuel technologies [e.g., liquid petroleum gas (LPG), biogas, electricity, ethanol] performed best overall, but households using them also fell short of the target. Stove stacking (using multiple stoves and fuels) and other pollution sources inside (e.g., kerosene lamps) and outside the home were likely explanations. These findings suggest that near exclusive, community-wide use of clean fuels is needed to meet the PM2.5 guideline and to maximize health benefits (Johnson and Chiang 2015). Most of the developed world, as well as the high-income populations in the developing world, have made the transition to cleaner fuels for cooking and other household energy needs (IEA 2015). While next generation solid fuel stoves may provide an important transitional technology with potential health benefits, this has yet to be demonstrated, and a recent study highlights the emission challenges these technologies face (Mutlu et al. 2016). Therefore, the challenge before the public health community is how to accelerate the movement of large numbers of lower-income people up the energy ladder to cleaner cooking, while recognizing that the transition to clean fuels will vary according to socioeconomic status and geography (Jeuland et al. 2015). In addition, stove and fuel stacking will continue to occur for a variety of reasons (Ruiz-Mercado and Masera 2015).